1. Field of the Invention
The present invention relates to a plug connector for providing a disconnectable rapid electrical coupling between preferably a plurality of conducting electrical contact elements insulated with respect to each other and an equal number of conductors disposed in a plug and to a method for making electrical connections.
2. Brief Description of the Background of the Invention Including Prior Art
Plug connectors for receiving and contacting of printed circuit boards are known in the art as female multipoint connectors. Metal springs serve as contact elements for the female multipoint connectors and such springs can be made for example from spring bronze. They provide the three functions of conducting the current, providing a contact and generating the contact pressure required for obtaining a suitable contact.
The contact pressure required for providing a problem-free contact is relatively large. With longer multiple contact strips there is therefore required a considerable total force for the inserting of the conductor plate. This force has to be overcome upon insertion of the printed circuit board by pressing apart the springs with the circuit board edges, which are bevelled for this purpose. The contact surfaces of the springs become considerably worn from the material of the printed circuit boards such as for example fiber-glass reinforced epoxyresin as well as from the sharp edges of the pulled conductors. Furthermore, the dimensions of the springs have to be kept relatively large to assure permanently sufficient spring forces. This in turn prevents a reduction in size of the multiple contact strips or respectively prevents an increase in the number of contacts with the same size of strip.
It is known that in zero insertion force connectors (sold for example by Cannon, DL-series) the spring properties of the springs are separated from the contacting properties. The contact pressure required for providing adequate contact between the contact elements of the one and the other plug element is provided after the force free insertion by a force provider such as for example a cam. The zero insertion force connectors are subject to only minor wear and assure a uniform contact pressure for all contact elements. In view of the present day construction of electronic instruments it is however a disadvantage, that the zero insertion force connectors have to be accessible from two sides that is first for the insertion of the board to be inserted and second for operation of the force provider. It is also disadvantageous that during the providing of the contact there is little rubbing between the contact surfaces or none and thus the thereby effected self-purification is small.
An electrical connector is known from European Patent application 0014511 (application number 80 200 104.0) where the contact elements exhibit only the properties of current conduction and contact providing, whereas the contact pressure necessary for providing contacts is generated by a force diverter during the insertion process. This force diverter is a permanent elastic element, which is compressed via profile surfaces upon insertion of the printed circuit board to be contacted. Based on the shape of the profile surface, the force diverter escapes in a cross direction to the plugging and thereby presses the by now next to each other positioned and with each other to be contacted connection elements against each other. A snap-in connection keeps the arrangement in connected position against the restoring force of the permanent elastic element.
In the above cited plug connector the contact pressure for providing of good contacts is generated during the step of insertion as is done in case of conventional multipoint contact strips. This is a considerable advantage as compared with the described zero insertion force connectors. A disadvantage of this arrangement is however that in the insertion state a permanent force is acting trying to press the printed circuit board again out of the connection by acting against the plug-in direction. In fact, this is prevented by the snap-in connection. This snap-in connection however is relatively complicated, since the available space is limited for example for an overlift motion for allowing the intended pulling out.